1. Field of the Invention
The present invention relates to drink dispensers and, more particularly, but not by way of limitation, to an apparatus and method for controlling a pump.
2. Description of the Related Art
A drink dispenser typically requires plain water for forming carbonated water and for dispensing either alone or with a syrup to produce a non-carbonated drink. As illustrated in FIG. 1, a water delivery system 50 receives plain water from a water source 51, such as a city water line. Unfortunately, such a water source 51 normally delivers plain water at less than 40 psi, which is a pressure below that required by the water delivery system 50. Consequently, the water delivery system 50 includes a water pump 52 that increases the water pressure to approximately 140 psi. The water pump 52 delivers the plain water to dispensing valves 55 and 56 and a carbonator 53 via a valve 54.
The carbonator 53, which is typically pressurized to 75 psi, connects to a carbon dioxide source that delivers carbon dioxide gas therein. The carbon dioxide gas diffuses/dissolves into the water thereby forming carbonated water. The valve 54, which is maintained closed at 75 psi, is a one-way check valve that prevents carbon dioxide gas and/or carbonated water from entering the water source 51.
The carbonator 53 includes a probe for regulating the level of water therein. The probe connects to a relay 57 that facilitates the delivery of power from the power source 58 to the water pump 52. When the probe registers the water level is below a preset level, it outputs a signal that closes the relay 57. The power source 58 delivers power to the water pump 52, which pumps water at approximately 140 psi from the water source 51 into the carbonator 53. When the probe registers the carbonator 53 is full, it deactivates its signal thereby shutting off the water pump 52.
The dispensing valves 55 and 56 also connect to the relay 57. When activated, the dispensing valve 55 and/or 56 outputs a signal that closes the relay 57 so that the power source 58 delivers power to the water pump 52. The water pump 52 pumps plain water to the activated dispensing valve 55 and/or 56, where it is either dispensed directly or mixed with a syrup to formulate a non-carbonated drink. Upon the deactivation of the dispensing valve 55 and/or 56, the relay 57 opens to remove power from the water pump 52.
Although the water delivery system 50 operates adequately to fill the carbonator 53 and supply dispensing valves 55 and 56 with plain water, it suffers a significant disadvantage. When the probe within the carbonator 53 controls the relay 57, the water delivery system functions properly because the dispensing valves 55 and 56 remain closed, however, when a dispensing valve 55 and/or 56 controls the relay 57, the carbonator 53 is filled regardless of its current water level. Upon the activation of a dispensing valve 55 and/or 56, the water pump delivers plain water at 140 psi. Consequently, the carbonator 53 fills because the plain water delivered at 140 psi overcomes the valve 54 so that the carbonator 53 receives plain water even though it may already contain a sufficient amount of water. As a result, the carbonator 53 overfills, which is a problem because, at a minimum, it alters the ratio of carbon dioxide and plain water, thereby ruining drink quality, and, at a maximum, it damages the carbonator 53 or potentially creates the dangerous situation where the carbonator 53 ruptures.
Accordingly, an apparatus and method that eliminates carbonator overfill during the delivery of plain water to dispensing valves will improve over currently available plain water pump controllers.